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Derivation of hydrodynamics for the gapless mode in the BEC-BCS crossover from the exact one-loop effective action

Da-Shin Lee·Chi-Yong Lin·Ray J. Rivers
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Abstract

We show that many hydrodynamical properties of the BEC/BCS crossover in the presence of a Feshbach resonance at T=0 can be derived easily from the derivative expansion of the (exact) fully renormalized one-loop effective action. In particular, we calculate the velocity of sound throughout the BCS and BEC regimes and derive the generalized superfluid continuity equations for the composite two-fluid system.

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Da-Shin Lee, Chi-Yong Lin, Ray J. Rivers. 2006-12-11. Derivation of hydrodynamics for the gapless mode in the BEC-BCS crossover from the exact one-loop effective action. https://doi.org/10.1103/physrevlett.98.020603

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